Apparatus for setting rivets



Sept. 25, 1962 w. s. SEH-'ERT APPARATUS FOR SETTING RTvETs Filed Aug. 28, 1959 ,NNN

United States Patent Otlce 3,055,528 Patented Sept. 25, 1962 3,055,528 APPARATUS FR SETTING R11/ETS Wilbur S. Seifert, Mount Vernon, ind., assigner to Whirlpool Corporation, a corporation of Delaware Fiied Aug. 28, 1959, Ser. No. 836,677 1 Ciaim. (Ci. 21S-42) This invention relates to an apparatus for setting rivets of the type having a tubular portion with a head at one end and an expanding member in the tubular portion adapted when subjected to a pulling force relative to the tulular portion to form a second head at the opposite en This type of rivet is well known and widely used for securing two pieces of material such as two sheets of metal together. It is a type of blind rivet in which the rivet extends through aligned openings in the sheets of material and the pulling force is exerted on the expanding member while a pushing force is exerted on the external end of the rivet in order to form a second head on the internal end of the rivet and attach the two pieces of material securely together. Not only is this type of rivet well known and widely used but the apparatus for setting such a rivet is also well known and widely used.

In one type of apparatus for setting such a rivet an .l anvil bears against the external head of the rivet with a reactive force that is opposite to the pulling force on the expanding member that is exerted by the apparatus.

The apparatus of this type is customarily powered by pneumatic or hydraulic force. In the customary blind rivet setting tool the anvil must be held with its rivet engaging surface exactly even and parallel with the outer or working surface of the outer piece of material being joined so that the rivet will align precisely in its opening in the pieces of material.` This is necessary in order to prevent shifting of the rivet in its opening during the setting of the rivet which would leave an edge gap on one side. The inspection requirements on such rivets are usually extremely severe. Thus with countersunk blind rivets of this type that are used in airplane construction there must be not more than a 0.002 inch spacing between the head of the rivet and the opening in which it is located at any point on the periphery of the rivet. This of course is a severe requirement and a very high percentage of the rivets installed in the customary manner fail to pass this test. However, by using the apparatus of this invention the percentage of rivets that fail to pass this test are cut to a very small fraction of the total that fail to pass the test when using conventional rivet setting apparatus.

The present invention avoids this difiiculty by providing an angular rocking movement or swiveling between the anvil and the portion of the apparatus that engages the expanding member so that the anvil automatically shifts when necessary relative to this portion of the rivet gun to permit the rivet to align itself evenly in its opening before the pulling force is exerted. This insures setting the rivet securely and uniformly in its opening and relative to the outer or `working surface of the outer member being joined. Where in the former type of apparatus the rivet gun had to be held at exactly right angles to the outer surface of the outer material being joined with a tolerance of approximately 1, the apparatus of this invention permits movement of the rivet gun as much as vl" from the vertical without affecting the perpendicular alignment of the anvil.

One of the features of this invention therefore is to provide an improved apparatus for setting rivets of the above type in which means 'are provided for automatically `aligning the anvil at substantially right angles to the working surface of the material being joined.

Another feature of the invention is to provide an improved apparatus for setting rivets of this type by pulling on the expanding member with a pulling force while pushing on the head of the rivet about its periphery thereon with an opposite pushing force to form the second head and adjusting the angular relationship between these forces where necessary to apply the pushing force substantially uniformly to said area.

Other features and advantages of the invention will be apparent from the following description thereof taken in conjunction with the accompanying drawings. Of the drawings:

FIGURE 1 is a fragmentary longitudinal sectional view partially broken away of a blind rivet pulling apparatus embodying the invention,

FIGURE 2 is an end elevational view -of the head of FIGURE 1 taken from the left-hand end thereof.

FIGURE 3 is a fragmentary longitudinal sectional view through -this left-hand end of the pulling apparatus illustrating its relationship to two pieces of metal preparatory to being joined by a blind rivet.

FIGURE 4 is a fragmentary sectional view showing the set rivet in position -but before smoothing 4the outer end thereof.

FIGURE 5 is a fragmentary longitudinal sectional view through the left-hand end of the pulling apparatus illustrating its relationship with two pieces of metal while being assembled with a blind rivet, the pulling apparatus being shown canted to one side of a line perpendicular to the metal pieces.

The setting apparatus of this invention comprises a housing 10 having `an outer operating end 11 provided with a centrally located axially aligned and outwardly opening cavity or socket .12 therein. Positioned in this socket 12 is a rivet setting anvil 13 having an axial opening 1-4 therein expanded at its outer end ina conical section 15. The anvil 113 has an annular ilat rim 16 on the outer end of the anvil at the periphery thereof. The anvil 13 which is generally cylindricalfwith a round inner end 16a resting against the inner surface 20 of the socket 112 is held in place by a pair of axially aligning, diametrically extending ratchet pins 17. These ratchet pins have sloped inner ends litl within the opening 25 of the anvil 13 with the sloped portions thereof facing the front or conical end 15 of the anvil. The ratchet pins 17 are held in position by means `of a curved spring 19 engaging a groove 21 adjacent the end of each pin y17 but located inwardly of the outer surface 22 of the housing 10. The spring 19 has one end Z3 turned radially inwardly t0 occupy a similarly shaped opening in the housing 10 to aid in holding the spring in place.

The anvil is loosely mounted in the socket 12 for rocking movement relative thereto and the pins 17 are loosely mounted relative to the openings 24 in the housing 10 and openings 25 in the anvil -13 that are occupied by the pins.

A blind rivet of the type that is usable with the apparatus of FIGURE l is disclosed in FIGURE 3. This blind rivet 26 has a tubular portion 27 adapted to extend through aligned openings in two pieces of superposed sheet metal 228 and 29 or the like. The rivet has an outer head 30 of frustum shape provided with an essentially flat outer surface 31. The opening in the outer metal sheet 29 is countersunk as indicated at 32 to receive this head. iSlidably mounted within an axial opening 33 in the rivet 26 is an expanding member 34 having a shank 35 provided with spaced serrations 36 on an end of the shank 35 that extends outwardly beyond the head 30. On the inner or blind end of the member 34 the shank 35 is enlarged as indicated at 36a and is provided on its extreme inner end with an enlarged end I37. This type of rivet including the expanding member 34 is well known and Widely used in this type of installation.

V The portion of the apparatus for exerting the pulling force is contained within the hollow interior of the housing 10. This portion includes a generally cylindrical collet 3S having a hollow interior 39 dened at the front by an end portion 40. This end portion of the collet is provided with an opening 41 having the outer section thereof tapered toward the front of the apparatus. This opening 41, which is axially aligned with the opening 14 in the anvil and an opening 42 in a wall 43 that defines the bottom Z of the socket 12, is adapted to receive chuck jaws 44 of the customary type. These jaws are slidable within the opening 41 and are provided on their inner surfaces with serrations (not shown) adapted to engage 'the serrations 36 on the shank 35 of the expanding member. The jaws which are three in number are held in assembled relationship by means of a neoprene jaw retaining ring 45 extending around the outer surfaces of the jaws and held in an annular recess.

Bearing against the ear surfaces of the jaws 44 is the enlarged end 46 of a generally tubular jaw follower 47. This jaw follower is axially reciprocable within the hollow interior 39 of the collet 38. Extending around the follower 47 is a relatively weak helical spring 4S having one end bearing against the enlarged end 46 of the follower 47 and the other end bearing against a threaded extension 49 of a generally cylindrical drawbolt 50. This end 49 is threaded into the adjacent end of the collet 38, as vshown in FIGURE l, and the interior of this end 49 is hollow as indicated at 51 in order that the follower 47 may be telescopically received therein. The drawbolt 50 has a laterally extending opening `52 that cooperates with la similar opening in the housing so as to communicate with the exterior of the apparatus. lThis opening 52 is in communication with the opening 51 which in turn communicates with an axial opening 52 in the follower 47 which itself communicates with the interior of the jaws 44.

The section 53 of the drawbolt 50 that contains the opening S2 is of substantially the same outer diameter as the collet 38. The outer surfaces of both are adjacent the inner surface of the housing 10 and are slidable relative thereto. The rear end portion 54 of the drawbolt is of reduced diameter and has -the forward end of a relatively strong helical spring 55 arranged therearound. The forward end of this spring bears :against the rear end of the section 53 of the drawbolt. The rear end of this spring 55 bears against an inturned annular flange 56 that extends inwardly from a tubular retaining cap 57 that is provided with an internally threaded, enlarged inner end 58 that engages similar threads on the adjacent end of the housing 10. "I'he retaining cap 57 and housing 10 are of substantially the same outer diameter so that the cap S7 constitutes an extension of the housing y10.

A pneumatic or hydraulic operated blind rivet gun (not shown) of customary type is adapted to operate the force supplying portions of the apparatus. When this is done the threaded outer surface 59 of the retaining cap 57 is locked to the gun and an operating portion of the gun (not shown) is adapted to engage the threaded end cavity 60 on the end of the drawbolt 50. By this means the rearward pulling force is exerted on the drawbolt 50 which in turn exerts a pulling force on the collet 38 and the chuck jaws 44 in the customary manner.

`In operation the serrated end 36 of the expanding member 34 of a rivet assembly is inserted into the pulling apparatus through the anvil opening 14 and opening 42 to the interior of the chuck jaws 44. As the spring 48 is a weak spring the jaws are pushed back and the jaw follower 47 is also moved rearwardly. With the end 36 within the jaws 44 the spring 48 pushes the jaws against the inclined sides of the opening 41 to hold the jaws in engagement with the serrations. The rivet assembly is then inserted in the opening through the metal members 28 and 29 to the position shown in FIGURE 3. Because of the loose mounting of the anvil 13 as previously described and as shown in FIGURE 5, the anvil seats itself and thus the rivet at right angles to the outer surface of the member 29 even when the axis 65 of the housing 10 and the elements contained therein are at something other than a angle to this surface of the member 29. Thus with the apparatus of this invention the anvil and therefore the rivet is self-aligning so that its axis 65 is always at right angles to the member 29. In the embodiment shown the angle of the apparatus not including the anvil to the outer surface of the member 29 Varied as much as 10 from an exact vertical and the angle of the axis of the anvil 13 was still at 90 to this outer surface. The apparatus is then operated in the customary manner to move the drawbolt 50 and thus the jaws 44 sharply rearwardly. This results in a forward reactive force being exerted by the anvil 13 against the rivet head 30. This reactive force is applied to the anvil 13 through the housing `10. As shown in FIGURE 5, the shank 35 of rivet 26 is slightly bent during the pulling operation whenever the axis 65 of the housing `10 is not coincident with axis 66 of anvil 13 due to the fact that the direction of the pulling force is angularly displaced to one side or the other of axis 66.

As is customary the pulling force on the expanding member 34 causes the enlarged end 36a on this member to enter the tubular portion 27 of the rivet and expand it outwardly against the portions of the sheets 28 and 29 ldefining the aligned openings. Continued pulling causes the inner blind end of the portion 27 to expand radially to form a second and inner head 62. As is customary with rivets of this type continued pull on the member 34 causes the serrated end 36 to break, usually in the area of one of the serrations. The rivet connection is completed by cutting the expanding member 35 at a point beyond the rivet head 3i) as indicated at 63 in FIGURE 4. The rivet connection is completed by grinding down the extended portion of the member 34 until it is substantially Hush with the rivet head surface 31.

Then, when the next rivet shank 3S is inserted into the `anvil opening 14 it pushes the remainder of the previous rivet into the opening 52. This next rivet is fastened in a pair of aligned holes in the same manner and the operation completed. As the remainder of the rivets are moved rearwardly by the insertion of successive rivet shanks 35 these remaining portions fall through the opening 52 to the exterior of the apparatus.

As can be seen from the above description the anvil 13 which has an angular rockable mounting with respect to the axis 65 of housing 10 is always seated at a right angle to the outer surface of the member 29. This automatically insures proper alignment of the rivet in its opening. In addition in order to press the peripheral edge portion of the rivet head 30 securely against the metal member 29 the anvil bears against this surface 32 only at the peripheral edge because of the provision of the annular anvil contacting surface portion 16. As is shown in FIG- URE 3 the anvil contacts a rivet head only in this annular peripheral area.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified, but :rather be construed broadly within its spirit and scope as set out in the accompanying claim.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows:

Apparatus for settling countersunk rivets of the type having a tubular portion with a head at one end and an `expanding member in the tubular portion adapted when subjected to a pulling force relative to the tubular portion to form a second head at the opposite end, comprising: a housing member having a longitudinal axis; engaging means associated with said housing member and movable relative thereto adapted to engage said expanding member for exerting said pulling force; lan anvil having a surface adapted to seat on and bear against said head only in lan area at the periphery thereof with `a reactive force opposite to said pulling force; and means mounting said anvil on said housing lmember for angular rocking movement relative to said axis wherein said reactive force is applied substantially uniformly to said peripheral area.

References Cited in the file of this patent UNITED STATES PATENTS Quint Sept. 27, 1921 Jensen May 14, 1946 Van Heeke lan. 21, 1958 McIlvin Sept. 16, 1958 

